Katharine Selden Kniskern Mather (October 21, 1916 – February 4, 1991) was an American geologist with the United States Army Corps of Engineers, conducting research on cement and concrete.

[3] She attended St. Catherine's School in Richmond, Virginia, and earned a degree in geology at Bryn Mawr College in 1937.

From 1942 to 1982, she was a geologist with the U. S. Army Corps of Engineers, based in Vicksburg, Mississippi at the Waterways Experiment Station (WES).

[1][5] She served on the board of directors of the American Concrete Institute from 1968 to 1971, and as president of the Clay Minerals Society in 1973.

[6] Her papers are held in the Archives of Women in Science and Engineering, Special Collections Department, Iowa State University.